Project Summary /Abstract Shigella and enterotoxigenic Escherichia coli (ETEC) are two of the most important diarrheal pathogens worldwide, causing moderate-to-severe diarrheal disease in young children in developing countries and travelers' diarrhea among U.S. travelers who visit developing countries. We have developed a lead candidate prototype Shigella-enterotoxigenic Escherichia coli (ETEC) vaccine candidate strain, CVD 1208S-122, which consists of an attenuated ?guaBA,?set,?sen Shigella flexneri 2a strain engineered to express ETEC colonization factor antigen I (CFA/I) and the B and A2 subunits of heat-labile enterotoxin (LThA2B) from genes integrated into the chromosome. In animal models this prototype has elicited protective immune responses against these two important human diarrheal pathogens. The overall goal of this proposal is to translate this prototype Shigella-ETEC vaccine construct from an academic research laboratory vaccine candidate to a potential human vaccine ready to enter Phase 1 clinical trials (under other funding) to evaluate its safety, clinical tolerability, excretion pattern, transmissibility to close contacts, and immunogenicity. We have engaged an industrial partner, PaxVax, Inc. of Redwood City, CA. PaxVax is committed to becoming a future manufacturer of our multivalent combination vaccine and will provide overall strategic guidance for this translation, including regulatory support (in preparation of the chemistry/manufacture/control (CMC) portion of the IND, advice on interaction with contract manufacturing organizations (CMOs), and other industrial know- how. To accomplish this transition from promising research laboratory candidate to potential human trial, we propose the following activities. Aim 1. Technology transfer, Cell Bank production, process development and pilot scale-up of Shigella-ETEC vaccine candidate CVD 1208S-122. Aim 2: Comprehensive cGMP pilot production lot to provide 3000 vials of CVD 1208S-122. Aim 3: Comprehensive pre-clinical studies on the cGMP pilot lot formulation of CVD 1208S-122 to underpin submission of an IND to the FDA to prepare for Phase 1 and 2 clinical trials.